They are demanding extra money and/or a day off in lieu but transport bosses said their £46,000 salary already covers the bank holiday.

It would be the third successive Boxing Day strike by train drivers, hitting retailers at one of the busiest times of the year and stopping many families getting around the capital for traditional Christmas visits.

Similar strikes by Aslef, which controls more than half the Tube’s 3,300 trains, caused huge disruption on Boxing Day in 2010 and last year.

Each time Tube bosses failed in a legal challenge to get the strike called off. The crux of the dispute dates back to a 1992 agreement which saw staff getting higher salaries and increased annual leave in return for working “some” bank holidays.

Aslef says drivers are now working all or most bank holidays.

Previous demands have included triple salary for Boxing Day and a day off in lieu but Aslef refused to confirm if they were the same this year.

Three further strikes in January and February this year were called off to allow peace talks to take place.

Aslef general secretary Mick Whelan said: “We hope to get it resolved. The company has only recently agreed to sit around the table with us.”

He said if no deal was reached it is “quite likely” drivers will be balloted for strike action.

Drivers with the RMT union, which is not involved in the dispute, may refuse to cross picket lines.

Howard Collins, London Underground’s chief operating officer, said: “It would be quite wrong for the Aslef leadership to ballot for industrial action while we remain engaged in discussions to resolve this issue. There is a proposal on the table.”